Unless she had turned from me. — There may be an aposiopesis in this verse. Perhaps she turned aside from (or, before) me... for (otherwise) now I had killed thee, &c. According to this view the angel does not assign a reason why the ass turned aside, but leaves this to be inferred by Balaam. (Comp. Keil, in loc.)
Related Commentaries of Numbers 22:33
Numbers 22:33
33 And the ass saw me, and turned from me these three times: unless she had turned from me, surely now also I had slain thee, and saved her alive.